Such freewheel hubs are known from the prior art. Thus, for example the document DE 198 47 673 A1 shows a freewheel hub in which the two clutch rings are biased towards one another in each case via a spring assigned thereto.
The document DE 10 2012 016 945 A1 discloses a hub which has a hub body and a drive device. A cogset can be attached to the drive device. A ratchet freewheel between the drive device and the hub body allows a freewheel function. The ratchet freewheel has two engagement components which are embodied as star ratchets. The star ratchets have axial tooth sets which can be brought into engagement with one another. A magnet device is inserted in each case into a receiving space in the star ratchets. In this case, the magnet devices are arranged such that the south pole of one magnet device is arranged adjacent to the north pole of the in each case other magnet device. The magnet devices form a traction device which ensures that the two star ratchets are pretensioned into their engaged position.
A freewheel hub having magnet devices is also known from the document DE 10 2012 016 949 A1.
Furthermore, the document DE 10 2012 020 472 A1 discloses a freewheel hub in which the two clutch rings, as seen in a section containing the axis, have a stepped wall thickness profile with a portion of greater wall thickness and a portion of reduced wall thickness. A tooth set is formed in a central radial region of the clutch rings, in each case in the portion of greater wall thickness. In one of the two clutch rings, the portion of reduced wall thickness is formed radially inside the tooth set, adjoining the latter. In the other of the two clutch rings, the portion of reduced wall thickness can be formed radially outside the tooth set, adjoining the latter.
The above-described freewheel hub has proven to be highly successful in practice. However, it has been found that the known freewheel hubs tend, in particular in road bicycle racing, to produce or emit a relatively large amount of noise. The reason for this is that wheels, for example high-profile carbon rims, are becoming increasingly rigid and lightweight and can thus transmit and amplify vibrations and oscillations that arise in the freewheel hub all the better. In particular in combination with a high-profile carbon rim, a wheel forms an optimum acoustic body which can transmit and amplify the oscillations and thus noises that arise in the freewheel hub.
It is therefore an object of the present invention to provide a freewheel hub with which the noise production of the freewheel hub and of the freewheel hub in combination with the wheel can be reduced. It is a further object of the present invention to provide a freewheel hub in which the dead angle of the freewheel is relatively small and the freewheel torque at high speeds is as low as possible.